.container {
    width: 60%;
    margin: 0 auto;
    background-color: aqua;
    min-height:220px;
}
h2 {
    text-align:center;
    padding-top:10px;
}
p {
    width:90%;
    margin: 0 auto;
    text-align:center;
}
input {
    box-sizing: border-box;
    width: 60px;
}
p#result {
    margin:20px auto;
    height: 40px;
    width: 75%;
    padding: 20px;
    border: 1px dotted goldenrod;
    background-color:rgb(22,220,220);
    font-weight: bold;
}